online version

src/Terrain.cc

@@ -30,39 +30,9 @@ ElevationProvider::ElevationProvider(QObject* parent)
 
 }
 
-bool ElevationProvider::queryTerrainData(const QList<QGeoCoordinate>& coordinates)
+bool ElevationProvider::queryTerrainDataPoints(const QList<QGeoCoordinate>& coordinates)
 {
-    if (coordinates.length() == 0) {
-        return false;
-    }
-
-    bool fallBackToOnline = false;
-    QList<float> altitudes;
-    foreach (QGeoCoordinate coordinate, coordinates) {
-        QString uniqueTileId = _uniqueTileId(coordinate);
-        _tilesMutex.lock();
-        if (!_tiles.contains(uniqueTileId)) {
-            _tilesMutex.unlock();
-            fallBackToOnline = true;
-            break;
-        } else {
-            if (_tiles[uniqueTileId].isIn(coordinate)) {
-                altitudes.push_back(_tiles[uniqueTileId].elevation(coordinate));
-            } else {
-                qCDebug(TerrainLog) << "Error: coordinate not in tile region";
-                altitudes.push_back(-1.0);
-            }
-        }
-        _tilesMutex.unlock();
-    }
-
-    if (!fallBackToOnline) {
-        qCDebug(TerrainLog) << "All altitudes taken from cached data";
-        emit terrainData(true, altitudes);
-        return true;
-    }
-
-    if (_state != State::Idle) {
+    if (_state != State::Idle || coordinates.length() == 0) {
         return false;
     }
 
@@ -95,6 +65,47 @@ bool ElevationProvider::queryTerrainData(const QList<QGeoCoordinate>& coordinate
     return true;
 }
 
+bool ElevationProvider::queryTerrainData(const QList<QGeoCoordinate>& coordinates)
+{
+    if (_state != State::Idle || coordinates.length() == 0) {
+        return false;
+    }
+
+    QList<float> altitudes;
+    bool needToDownload = false;
+    foreach (QGeoCoordinate coordinate, coordinates) {
+        QString uniqueTileId = _uniqueTileId(coordinate);
+        _tilesMutex.lock();
+        if (!_tiles.contains(uniqueTileId)) {
+            qCDebug(TerrainLog) << "Need to download tile " << uniqueTileId;
+            _downloadQueue.append(uniqueTileId);
+            needToDownload = true;
+        } else {
+            if (!needToDownload) {
+                if (_tiles[uniqueTileId].isIn(coordinate)) {
+                    altitudes.push_back(_tiles[uniqueTileId].elevation(coordinate));
+                } else {
+                    qCDebug(TerrainLog) << "Error: coordinate not in tile region";
+                    altitudes.push_back(-1.0);
+                }
+            }
+        }
+        _tilesMutex.unlock();
+    }
+
+    if (!needToDownload) {
+        qCDebug(TerrainLog) << "All altitudes taken from cached data";
+        emit terrainData(true, altitudes);
+        _coordinates.clear();
+        return true;
+    }
+
+    _coordinates = coordinates;
+
+    _downloadTiles();
+    return true;
+}
+
 bool ElevationProvider::cacheTerrainTiles(const QGeoCoordinate& southWest, const QGeoCoordinate& northEast)
 {
     qCDebug(TerrainLog) << "Cache terrain tiles southWest:northEast" << southWest << northEast;
@@ -116,7 +127,7 @@ bool ElevationProvider::cacheTerrainTiles(const QGeoCoordinate& southWest, const
                 _tilesMutex.unlock();
                 continue;
             }
-            _downloadQueue.append(uniqueTileId.replace("_", ","));
+            _downloadQueue.append(uniqueTileId);
             _tilesMutex.unlock();
             qCDebug(TerrainLog) << "Adding tile to download queue: " << uniqueTileId;
         }
@@ -139,7 +150,7 @@ bool ElevationProvider::cacheTerrainTiles(const QList<QGeoCoordinate>& coordinat
             _tilesMutex.unlock();
             continue;
         }
-        _downloadQueue.append(uniqueTileId.replace("_", ","));
+        _downloadQueue.append(uniqueTileId);
         _tilesMutex.unlock();
         qCDebug(TerrainLog) << "Adding tile to download queue: " << uniqueTileId;
     }
@@ -233,12 +244,13 @@ void ElevationProvider::_downloadTiles(void)
         QUrlQuery query;
         _tilesMutex.lock();
         qCDebug(TerrainLog) << "Starting download for " << _downloadQueue.first();
-        query.addQueryItem(QStringLiteral("points"), _downloadQueue.first());
+        query.addQueryItem(QStringLiteral("points"), _downloadQueue.first().replace("_", ","));
         _downloadQueue.pop_front();
         _tilesMutex.unlock();
         QUrl url(QStringLiteral("https://api.airmap.com/elevation/stage/srtm1/ele/carpet"));
         url.setQuery(query);
 
+        qWarning() << "url" << url;
         QNetworkRequest request(url);
 
         QNetworkProxy tProxy;
@@ -253,6 +265,8 @@ void ElevationProvider::_downloadTiles(void)
         connect(networkReply, &QNetworkReply::finished, this, &ElevationProvider::_requestFinishedTile);
 
         _state = State::Downloading;
+    } else if (_state == State::Idle) {
+        queryTerrainData(_coordinates);
     }
 }
 

src/Terrain.h

@@ -38,7 +38,15 @@ public:
 
     /**
      * Async elevation query for a list of lon,lat coordinates. When the query is done, the terrainData() signal
-     * is emitted.
+     * is emitted. This call directly looks elevations up online.
+     * @param coordinates
+     * @return true on success
+     */
+    bool queryTerrainDataPoints(const QList<QGeoCoordinate>& coordinates);
+
+    /**
+     * Async elevation query for a list of lon,lat coordinates. When the query is done, the terrainData() signal
+     * is emitted. This call caches local elevation tables for faster lookup in the future.
      * @param coordinates
      * @return true on success
      */
@@ -80,6 +88,7 @@ private:
 
     State                       _state = State::Idle;
     QNetworkAccessManager       _networkManager;
+    QList<QGeoCoordinate>       _coordinates;
 
     static QMutex                       _tilesMutex;
     static QHash<QString, TerrainTile>  _tiles;

src/TerrainTile.cc

@@ -141,8 +141,8 @@ float TerrainTile::elevation(const QGeoCoordinate& coordinate) const
     if (_isValid) {
         qCDebug(TerrainTileLog) << "elevation: " << coordinate << " , in sw " << _southWest << " , ne " << _northEast;
         // Get the index at resolution of 1 arc second
-        int indexLat = std::round((coordinate.latitude() - _southWest.latitude()) * gridSize / srtm1TileSize);
-        int indexLon = std::round((coordinate.longitude() - _southWest.longitude()) * gridSize / srtm1TileSize);
+        int indexLat = round((coordinate.latitude() - _southWest.latitude()) * (gridSize - 1) / srtm1TileSize);
+        int indexLon = round((coordinate.longitude() - _southWest.longitude()) * (gridSize - 1) / srtm1TileSize);
         qCDebug(TerrainTileLog) << "indexLat:indexLon" << indexLat << indexLon; // TODO (birchera): Move this down to the next debug output, once this is all properly working.
         Q_ASSERT(indexLat >= 0);
         Q_ASSERT(indexLat < gridSize);

src/TerrainTile.h

@@ -5,7 +5,7 @@
 
 #include <QGeoCoordinate>
 
-#define TERRAIN_TILE_SIZE 90
+#define TERRAIN_TILE_SIZE 91
 
 Q_DECLARE_LOGGING_CATEGORY(TerrainTileLog)